Tape Machine Style Monitoring Not Working

At some point recently Tape Machine Style Monitoring stopped working. According to the documentation:

“Tapemachine Style This option emulates standard tapemachine behavior: input monitoring in Stop mode and during recording, but not during playback.”

When the monitoring button is lit and Cubase is playing, I dont hear what is recorded on the track.
If the monitoring button is lit, no matter whether I am playing, stopped, or recording, I hear the input to the track.

I’ve reset the option a few times just to see if it was glitchy, but no joy.

Any obvious ideas I might be missing?